327 - 11th Botany Textbook Volume 1

I. Characteristic features
• Root is the descending portion of the
plant axis.
• Generally non-green in colour as it
lacks chlorophyll.
• Does not possess nodes, internodes and
buds (Exception in sweet potato and
members of Rutaceae, roots bear buds
which help in vegetative propagation)
• It bears root hairs (To absorb water
and minerals from the soil)
• It is positively geotropic and negatively
phototropic in nature.
II. Regions of root
Root tip is covered by a dome shaped
parenchymatous cells called root cap.
It protects the meristematic cells in the
apex. In Pandanus multiple root cap is
present. In Pistia instead of root cap root
pocket is present. A few millimeters above
the root cap the following three distinct
zones have been classified based on their
meristematic activity.
1. Meristematic Zone
2. Zone of Elongation
3. Zone of Maturation
Root hair
Region of Cell
maturation
Region of cell elongation
Region of cell division
Root cap
Figure 3.2: Regions of root
Feature
Position
Table: Root zones
1. Meristematic Zone 2. Zone of
(Region of cell division ) Elongation
It lies just above the It lies just above the
root cap
meristematic zone
3. Zone of Maturation
It lies above the zone
of elongation.
Types of
cells
Functions
Meristematic cells,
actively divide and
continuously increase
in number
This is the main
growing tip of the
root
Elongated cells
The cells increase
the length and cause
enlargement of the
root.
Mature differentiated
cells
The cells differentiate
into various tissues like
epidermis, cortex and
vascular bundles. It
also produces root hairs
which absorb water and
minerals from the soil
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